Federica Dolci has done a lot of research on oil mill technologies, studying in detail all the steps from the collection of the raw material to the conservation of the extra virgin olive oil. For us not only it is important to produce an oil which is unique in its genre, but also to be environmentally friendly, for this reason we have selected a machine for the cold extraction of the oil, with a two-step process.
All this allows:
1. Using very small quantities of water during processing.
2. The by-product which is obtained by the extraction of the oil is a very humid pomace, from which we extract the stone which has a calorific value equal to 5000Kcal/Kg, with respect to the common pellets. The residual olive pulp material, devoid of the stone, is used in many fields, as zootechnical integrator, adding lipids with high biological value and antioxidants to the diet of the animal, as a fertilizer or for the production of biogas.
Our production process, consists first of all in the choice of an excellent raw material, both in terms of level of ripeness, and for the range of deficiency. We preferably use product harvested by hand and conferred in small boxes, in order to allow adequate ventilation of the product and to avoid that the drupe may be damaged and that fermentation processes may trigger more quickly.
The washing and defoliation step consists in the addition of clean water jets and in drying the olive, in order to avoid transferring the microbial component present on the outside of the fruit in the finished product. The crushing: aromatic production phase, where a series of enzymes present in the fruit, which are catalysts of enzymatic reactions, responsible of the sensorial characteristics and health benefits of the oil are activated. The most characteristic aspect is that the main polyphenols including oleuropein, during this phase pass from the cytoplasmic portion of the fruit to the oily one. During this phase however also enzymes such as peroxidase and polifenoloxidase that may have a negative impact on the quality of the product are activated. The distribution of these enzymes is different in the various parts of the fruit, for this reason we recurred to a differentiated crushing, i.e. a process of degradation of the tissues of the fruit accentuated on the epicarp and on the mesocarp, while the impact on the stone is much more bland, allowing in this way a small passage of the peroxidase (enzyme that is abundantly present in the stone) in the paste, responsible for oxidation of phenolic compounds during kneading.
Kneading is the step that follows the crushing, where the mixing of olive paste and the slight heating produce the breaking of the water-oil emulsion, allowing the oily droplets to join into bigger droplets, which will more easily segregate from the aqueous phase in the next process of solid-liquid (paste- oil+water) and liquid-liquid (vegetation water-oil) separation. Peroxidase and polifenoloxidase enzymes freed and activated during the crushing, catalyse the oxidative degradation of phenolic compounds at a determined temperature and especially during the kneading. In addition, these enzymes are active in the presence of oxygen, for this reason our kneading machines operate in the absence of gas exchange, inhibiting the activity of these enzymes. The solubility of phenolic compounds in oil is a function of the temperature and therefore in the absence of oxygen the transfer from the solid phase to the oily phase and to the vegetation water is favoured.
The aromatic note of the oil originates in part from the activities of the lipoxygenase during kneading, which leads to the formation of aldehydes, alcohols and saturated and unsaturated esters, or volatile substances to which are associated various notes like "fresh herbaceous", "flowers", feeling of "tomato". The optimal temperatures of the enzymes responsible for the production of these aromas is between 15°C to 25°C, for this reason, thanks to a monitoring system, we can control and change the temperature of the processed material in every moment in real time.
Finally, the pulp is subjected to centrifugal separation with the two stages decanter and is immediately filtered and stored in stainless steel tanks, where through the use of nitrogen, we replace the oxygen overlying the oil, reducing the processes of oxidative degradation to a minimum and allowing a conservation of the finished product at the highest levels.